<!DOCTYPE html>
<html lang="zh_CN">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        .box{
            display: flex;

            /*主轴是垂直，交叉轴是水平*/
            flex-direction: column;
            /*justify-content: flex-start;*/
            justify-content: space-evenly;

            /*交叉轴是水平方向，宽度如果没有设置就是拉伸*/
            align-items: stretch;

            width: 500px;
            height: 500px;
            border: 1px solid red;
        }

        .box1{
            /*width: 100px;*/
            height: 100px;
            background-color: #f00;
        }

        .box2{
            /*width: 100px;*/
            height: 100px;
            background-color: #0f0;
        }

        .box3{
            /*width: 100px;*/
            height: 100px;
            background-color: #00f;
        }


    </style>
</head>
<body>
    <div class="box">
        <div class="box1"></div>
        <div class="box2"></div>
        <div class="box3"></div>
    </div>
    文本
</body>
<script type="text/javascript">

</script>

</html>
